RFID-Based Auto-lock/unlock System

02-17-2012, 03:51 PM

I'm looking to build a standalone system to use RFID with approx 2-3 meter range that will detect a RFID tag.
Upon detection of the proper RFID, I will have a OEM remote board wired into the system so it unlocks the doors.
When the RFID is no longer detected, I want it to lock the doors, then set the alarm (double button press of the 'lock' button)

The problem here is that I don't even know where to start. I've seen RFID kits but I don't know what to get. I don't want to bother with Bluetooth because the systems are crazy expensive. Once that is established I need a low-power intelligent system to make connections to correctly simulate a button press.

I'm not against a Fusion-brain for this, but I can't find any kind of RFID integration for it. Arduino might be better, but IIRC, PaulF had a very nice, arduino-based system that ended up drawing too much power at idle and killed his battery while his car was parked.

This will not be reading my factory keys' RFID chip, but this will be a separate system just to automatically hit the lock and unlock buttons for me using circuitry pulled from a spare remote. Existing remotes/keys will still operate normally, is the plan. So something that constantly sends a 'lock' signal while I'm away from the car is the wrong idea. Just need it to lock when detection first fails.

Any help on this project would be immensely appreciated. I know this is the community to get this kind of thing done.

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My concern with an active system is battery draw. I also want to keep the RFID chip small as I will be adding it to my OEM key fobs. I will read about the OpenBeacon Project, though. If nothing else, it may provide insight on how to build this system.

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My concern with an active system is battery draw. I also want to keep the RFID chip small as I will be adding it to my OEM key fobs. I will read about the OpenBeacon Project, though. If nothing else, it may provide insight on how to build this system.

Passive is going to limit you to a range or 1-12". You should be able to design an active rfid system using openbeacon as a guide that pulls very little current, but you're probably going to have to spin your own pcb's and fab it up yourself, unless anyone else knows of a project that does something similar?

"stop with the REINSTALLS, what do you think we got some lame-o installer!!!" - mitchjs
RevFEMy Shop

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you can put arduino into a watchdog mod that should reduce the current draw drastically. you could have it look for your rfid tag ever 15 seconds, instead of thousands of times a second. that openbeacon thing is awesome too. that would open your window for scannign for the device. if the range is 100' for instance. then you could have it scan every 30 seconds as it would take you that long to walk to your car from 100 feet.

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When I had my Blazer I was looking into something like this along with keyless ignition after driving the new Kia Sorrento that needed only for the key to be in your pocket to open the door and start the vehicle. I was gonna use the K9 Sombra for the bluetooth part. I could not get any real reviews for the unit so it would have been a gamble. I was also looking into the RFID route but never got too deep into researching it. You are right though, the kits for such things are pricey which is why I was trying to come up w/ a cheaper ingenious way of doing it instead.

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My reasoning behind it is a little more complicated than what this RFID system, itself, will do.

Initially, I'd decided I really wanted to do a push-button start. This will involve going so far as to remove the key cylinder on the steering column. I'll have a rocker switch: neutral for OFF, down for ACC, up for ON, simple wiring into the ignition switch there. The Start button will also be simple as a press is like turning the key forward past "ON". Yes, it's a bit of a dummy system, but it's easy and my car has never had an issue starting quickly (it's a 2005).

Well, I don't want to disable the immobilizer completely, because then I would run a huge risk for anyone breaking into my car and simply driving off. I had shelved this idea for some time because of the security risks. Recently, I heard about the Aston Martins having that amazing "crystal key" (or 'Emotional Control Unit', as they call it) that is inserted into the dash. This is where I wanted to go with the immobilizer chip. So I will fabricate a few of these remotes and use my existing keys' chips. The sensor in the car will be moved from the steering column to the slot this fob will go into. The fobs will be modified Honda remotes, programmed to my car with proper immobilizer chips. The RFID will be added as a way of automatically opening my doors for me, a feature I fell in love with when test-driving an Acura RL. So these fobs will house the remote module that the fancy honda keys have, plus the RFID to trigger this system I'm trying to build.

The remote module I wire into the RFID system will NOT have an immobilizer chip programmed to my car. It would technically be safe, given the range of the reader is only a few inches for that.

I first wanted to use parts salvaged from an RL to integrate the immobilizer chip into operating this unlock feature, but even though these are parts that don't even get cataloged (are usually destroyed with the remains of a salvage vehicle) it would have required me to hack my ECU to make it work properly, I was told. Right now, that's out of the question. I've yet to find anyone who had been able to get into the ECU of any 2003-2007 Honda Accord, nevertheless one of the rare, hybrid models.

Looking at this, though, the RFID module doesn't appear to have the stuff to program the RFID tags. That may require one of those kits, which can be had for around $100, but I'm still unsure what to buy.

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I think you could incorporate the always on SheevaPlug that someone used in a Volvo if I'm not mistaken. You might be able to write a very simple script if all you need is LOCK / UNLOCK state and PRESENCE of key fob.

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I think you could incorporate the always on SheevaPlug that someone used in a Volvo if I'm not mistaken. You might be able to write a very simple script if all you need is LOCK / UNLOCK state and PRESENCE of key fob.

Is that what PaulF used? He had a rockin setup in his Volvo but said it was too hard on the battery & he was working on a new setup with less draw at idle.

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I have a pretty simple setup in my car. Cheap rfid reader from ebay wired into the central locking.
Reading distance is through metal/glass so the card/fob has to be within 10cm for it to unlock/lock but that is all I really need.

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i have really started thinking about this, and the obstacle i am running into is getting both lock and unlock functions from the modules.

i can easily get the module to lock, or unlock the car by presenting a different key, but am unsure how i could do it with a single key--i'm thinking of using a present2 or present3 rule to unlock the car, but i don't see any rfid stuff that works that way..(most of the expensive stuff i've worked with before uses a present3 rule to keep power applied to the door mechanism to keep it unlocked until another present3 event is actuated..)

looking at this redbee reader right now(link)-- that has the amount of outputs i need, and plenty of cards, and can operate in standalone, i just need to figure out the lock/unlock issue..

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My reasoning behind it is a little more complicated than what this RFID system, itself, will do.

Initially, I'd decided I really wanted to do a push-button start. This will involve going so far as to remove the key cylinder on the steering column. I'll have a rocker switch: neutral for OFF, down for ACC, up for ON, simple wiring into the ignition switch there. The Start button will also be simple as a press is like turning the key forward past "ON". Yes, it's a bit of a dummy system, but it's easy and my car has never had an issue starting quickly (it's a 2005).

if you're going with the arduino why not program the functions into a single button. tap the button to switch the 'acc' relay, tap again to switch it off 'off', long press the button (with an input from your brake light to make sure you're pressing the brake) to engage the 'crank/starter' and the 'on' relay, release and have it disengage the crank relay but leave the 'on' relay engaged. tap again to shut off the car. it would be much cleaner and more professional looking